I bought a 2008 F150 5.4L Flex fuel with 140k miles about a year ago with a known timing issue, but it ran fine (other than a really ugly idle) after we threw fresh sparkplugs in it, so I just dealt with it until about April.

April it stalled on me for the first time while driving. Just totally died, check engine light on, battery light on, radio and cabin air still going, but no power or power steering. Would not restart until the engine cooled down, then it would run a bit, die again, run a bit, die again. Eventually it calmed down and let me drive home.

This started happening more frequently, and eventually I threw in the towel and did the timing job. On cracking open the timing cover, saw that the passenger-side static guide was shattered and pieces were all over. Picked out what I could, swapped in fresh timing chains, phasers, solenoids, looked over the camshafts and was satisfied with them, so I stitched it back up and after the idle relearn it ran like a new truck. Except that the random dying continued, and got more frequent as time went on.

Father-in-law thought fuel was the issue, so we checked out the FPDM and saw it had been replaced, new one had a little pitting on the backside of the case but looked intact, so we did a fuel pump, figuring it probably needed it soon anyway. Also fresh fuel filter. No improvement.

With more frequent stalls, I started carrying a code reader and pulling codes whenever it died on me. Usually there weren't any, but sometimes it threw timing-related codes or camshaft / crankshaft position sensor codes, so I replaced all three of those sensors. No change.

Recently it gave me a new code around the throttle body / MAS, so those both got swapped and a new air filter / scrub down of the air box were done as well. No change.

Given that it only dies at temp, and starts right back up once it cools down, I figured maybe oil pump, so am midway through that replacement (waiting on parts) as these trucks seem to have quite a reputation for the oil pump being undersized. When I cracked the timing cover off again, the driver-side chain looked right, all tensioned up and tight, but the passenger-side had some slack to it. It'd been sitting a few days, not sure if it maybe bled out some oil pressure through the leaky system over time? Also noticed that the little timing sprocket wheel thing that the crankshaft position sensor reads was a little chewed up on the backside, probably from the year with the bad timing slack, so I've got a new one of those on order. And I'm actually dropping the oil pan to fully scrub out any debris from the grinding / nastiness that developed from the loose timing chain before.

Any ideas on what else could be the issue here? I'm getting a bad feeling that this will be yet another case of replacing some parts that were probably on their way out, but not the cause of my current problem.

 

Well you should have cleaned out the oil pickup screen and oil pan when you did the timing job, so all the new parts would have a good chance but I'm not trying to needle you, live and learn.

Hopefully it hasn't damaged any parts with oil starvation.
Did you check the crankshaft endplay?
2007 and I think 2008 are known to have thrust bearing failures.

 

You're absolutely right that I should have done that then, the timing job was by far the deepest I've ever gone into an engine and I've learned a lot since then.

​​​​​​Did check play and wasn't anything noticable

 

I feel your pain. I just did the timing job on my truck. The passenger guide was in pieces just like you said.
I wasn't having any stalling issues, and my oil pressure was still good at hot idle (25psi on mechanical gauge) but it had been making the knocking noise after it was warm ever since I got it 3 yrs ago and was starting to have more start up rattle.there was quite a few small chunks of plastic in the oil pump pickup screen even though I didn't have much junk in the oil pan, so I'd encourage you to remove the tube while doing the oil pump and use a pick and maybe spray brake clean or something down from inside the tube to make sure all the gunk gets flushed out of the screen.
I put in a melling m340hv and now my hot idle pressure is 35 psi.
If your endplay is ok and the camshaft journals aren't all scored and egg shaped you probably have a fighting chance of reviving it I'd guess.

 

We have nothing to do with your ghost -wrong forum .
I would suggest that you carefully evaluate your injectors . You must be over 200k now , I just replaced mine again ,first was at 130k second set at 258k . They can ruin your engine . My last set no 2 was spray a solid stream with no signal on it no 5 was dripping . you can lay them out on dry newspaper none should drip with key on .
You need to use torque pro to see what your problem may be , fuel trims etc , o2 switching .
The parts cannon does not work .
I wonder if your clt head temp sensor is triggering either false or true. How hot do you think this engine is getting . Any chance your cats are starting to block . Some testing is going to be needed.

 

Using torque pro screen shots and posting on here for help will be a good way to go . Especially if you can get something when it breaks down . Fuel rail pressure will be shown . One thing you can do is to see how fast pressure drops off after shutdown or during a problem shutdown
Mine was dropping off to quickly sometimes so I thought it was the fuel pump check valve but no it was bad injectors . it was a bear changing fuel pump and we damaged nylon fuel line . We had to make our own from after market parts . Costly bad guess , but a shop would have hit me for over a 1000 bucks plus parts .

 

sounds like you (or FIL) jumped to a fuel issue. But did you do any testwork to confirm it was a fuel issue and not a spark/fire problem ?
(Sorry if I missed something, I scanned through posts fairly quickly)